The Diagnostic and Clinical Significance of TFE3 Immunohistochemical Nuclear Expression in Solitary Fibrous Tumour

Metastatic Epithelioid Pleomorphic Liposarcoma in the Brain: A Case Report

Metastatic soft tissue sarcoma (STS) to the brain is rare, and metastatic pleomorphic liposarcoma (PLPS) to the brain is even rarer. We present the case of a 76-year-old male with an incidental finding of a brain mass on a brain magnetic resonance imaging (MRI) following a head injury. Additionally, multiple pulmonary nodules and a right gluteal mass were discovered. A core biopsy of the right gluteal mass revealed an epithelioid malignant neoplasm expressing transcription factor enhancer 3 (TFE3) by immunohistochemistry (IHC). Subsequently, the left middle fossa brain mass was removed and found to be an epithelioid PLPS, which was positive for TFE3 by IHC but lacked TFE3 rearrangement by fluorescence in situ hybridization (FISH), and negative for murine double minute (MDM2) amplification by FISH. The diagnosis of epithelioid PLPS mainly relies on histomorphology. This paper discusses the clinicopathological correlation of PLPS, including the epithelioid variant, with a focus on cases with brain metastases.

Expression of TFE3 in Cellular and Myxoid Type of Neurothekeoma: Four Cases in Young Children and Adolescents

Introduction: Cellular neurothekeoma is a benign tumor that mainly occurs in young children and adolescents. The aberrant expression of transcription factor E3 (TFE3) has not been reported in cellular neurothekeoma previously. Case report: We report four cellular neurothekeoma with aberrant immunohistochemical expression of TFE3 protein. The fluorescence in situ hybridization (FISH) showed no TFE3 gene rearrangement or amplification. Discussion/Conclusion: TEF3 protein expression may not be related to TFE3 gene translocation in cellular neurothekeoma. TFE3 may be a potential pitfall in diagnosis, for several malignant tumors in children also express TFE3. The aberrant expression of TFE3 may offer insights into cellular neurothekeoma etiology, and associated molecular mechanisms.

A review of neoplasms with MITF/MiT family translocations

Microphthalmia-associated transcription factor (MITF/MiT) family is a group of basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factors including TFE3 (TFEA), TFEB, TFEC and MITF. The first renal neoplasms involving MITF family translocation were renal cell carcinomas with chromosome translocations involving ASPL-TFE3/t(X;17)(p11.23;q25) or MALAT1-TFEB/t(6;11)(p21.1;q12), and now it is known as MiT family translocation RCC in 2016 WHO classification. Translocations involving MITF family genes also are found in other tumor types, such as perivascular epithelioid cell neoplasm (PEComa), Alveolar soft part sarcoma (ASPS), epithelioid hemangioendothelioma, ossifying fibromyxoid tumor (OFMT), and clear cell tumor with melanocytic differentiation and ACTIN-MITF translocation. In this review, we summarize the features of different types of neoplasms with MITF family translocations.